Re #21 - Add matchall filter type

This tc filter matches all packets that encounter it.

Author: Erich Heine

src/rtnl/tc/constants.rs

@@ -20,6 +20,15 @@ pub const TC_H_MIN_PRIORITY: u32 = 0xFFE0;
 pub const TC_H_MIN_INGRESS: u32 = 0xFFF2;
 pub const TC_H_MIN_EGRESS: u32 = 0xFFF3;
 
+// matchall filters
+pub const TCA_MATCHALL_UNSPEC: u16 = 0;
+pub const TCA_MATCHALL_CLASSID: u16 = 1;
+pub const TCA_MATCHALL_ACT: u16 = 2;
+pub const TCA_MATCHALL_FLAGS: u16 = 3;
+pub const TCA_MATCHALL_PCNT: u16 = 4;
+pub const TCA_MATCHALL_PAD: u16 = 5;
+pub const TCA_MATCHALL_MAX: u16 = TCA_MATCHALL_PAD;
+
 /// U32 filters
 pub const TCA_U32_UNSPEC: u16 = 0;
 pub const TCA_U32_CLASSID: u16 = 1;

src/rtnl/tc/nlas/filter/matchall.rs

@@ -0,0 +1,94 @@
+// SPDX-License-Identifier: MIT
+
+/// Matchall filter
+///
+/// Matches all packets and performs an action on them.
+use anyhow::Context;
+use byteorder::{ByteOrder, NativeEndian};
+use netlink_packet_utils::{
+    nla::{self, DefaultNla, NlaBuffer, NlasIterator},
+    parsers::parse_u32,
+    traits::{Emitable, Parseable},
+    DecodeError,
+};
+
+use crate::tc::{constants::*, Action};
+pub const KIND: &str = "matchall";
+
+#[derive(Debug, PartialEq, Eq, Clone)]
+#[non_exhaustive]
+pub enum Nla {
+    Unspec(Vec<u8>),
+    ClassId(u32),
+    Act(Vec<Action>),
+    Pcnt(Vec<u8>),
+    Flags(u32),
+    Other(DefaultNla),
+}
+
+impl nla::Nla for Nla {
+    fn value_len(&self) -> usize {
+        use self::Nla::*;
+        match self {
+            Unspec(b) | Pcnt(b) => b.len(),
+            ClassId(_) | Flags(_) => 4,
+            Act(acts) => acts.as_slice().buffer_len(),
+            Other(attr) => attr.value_len(),
+        }
+    }
+
+    fn emit_value(&self, buffer: &mut [u8]) {
+        use self::Nla::*;
+        match self {
+            Unspec(b) | Pcnt(b) => buffer.copy_from_slice(b.as_slice()),
+            ClassId(i) | Flags(i) => NativeEndian::write_u32(buffer, *i),
+            Act(acts) => acts.as_slice().emit(buffer),
+            Other(attr) => attr.emit_value(buffer),
+        }
+    }
+
+    fn kind(&self) -> u16 {
+        use self::Nla::*;
+        match self {
+            Unspec(_) => TCA_MATCHALL_UNSPEC,
+            ClassId(_) => TCA_MATCHALL_CLASSID,
+            Act(_) => TCA_MATCHALL_ACT,
+            Pcnt(_) => TCA_MATCHALL_PCNT,
+            Flags(_) => TCA_MATCHALL_FLAGS,
+            Other(attr) => attr.kind(),
+        }
+    }
+}
+
+impl<'a, T: AsRef<[u8]> + ?Sized> Parseable<NlaBuffer<&'a T>> for Nla {
+    fn parse(buf: &NlaBuffer<&'a T>) -> Result<Self, DecodeError> {
+        use self::Nla::*;
+        let payload = buf.value();
+        Ok(match buf.kind() {
+            TCA_MATCHALL_UNSPEC => Unspec(payload.to_vec()),
+            TCA_MATCHALL_CLASSID => ClassId(
+                parse_u32(payload)
+                    .context("failed to parse TCA_MATCHALL_UNSPEC")?,
+            ),
+            TCA_MATCHALL_ACT => {
+                let mut acts = vec![];
+                for act in NlasIterator::new(payload) {
+                    let act = act.context("invalid TCA_MATCHALL_ACT")?;
+                    acts.push(
+                        Action::parse(&act)
+                            .context("failed to parse TCA_MATCHALL_ACT")?,
+                    );
+                }
+                Act(acts)
+            }
+            TCA_MATCHALL_PCNT => Pcnt(payload.to_vec()),
+            TCA_MATCHALL_FLAGS => Flags(
+                parse_u32(payload)
+                    .context("failed to parse TCA_MATCHALL_FLAGS")?,
+            ),
+            _ => Other(
+                DefaultNla::parse(buf).context("failed to parse u32 nla")?,
+            ),
+        })
+    }
+}

src/rtnl/tc/nlas/filter/mod.rs

@@ -1,3 +1,4 @@
 // SPDX-License-Identifier: MIT
 
+pub mod matchall;
 pub mod u32;

src/rtnl/tc/nlas/options.rs

@@ -7,7 +7,7 @@ use netlink_packet_utils::{
     DecodeError,
 };
 
-use crate::tc::{ingress, u32};
+use crate::tc::{ingress, matchall, u32};
 
 #[derive(Debug, PartialEq, Eq, Clone)]
 #[non_exhaustive]
@@ -16,6 +16,8 @@ pub enum TcOpt {
     Ingress,
     // Filter specific options
     U32(u32::Nla),
+    // matchall options
+    Matchall(matchall::Nla),
     // Other options
     Other(DefaultNla),
 }
@@ -25,6 +27,7 @@ impl nla::Nla for TcOpt {
         match self {
             Self::Ingress => 0,
             Self::U32(u) => u.value_len(),
+            Self::Matchall(m) => m.value_len(),
             Self::Other(o) => o.value_len(),
         }
     }
@@ -33,6 +36,7 @@ impl nla::Nla for TcOpt {
         match self {
             Self::Ingress => unreachable!(),
             Self::U32(u) => u.emit_value(buffer),
+            Self::Matchall(m) => m.emit_value(buffer),
             Self::Other(o) => o.emit_value(buffer),
         }
     }
@@ -41,6 +45,7 @@ impl nla::Nla for TcOpt {
         match self {
             Self::Ingress => unreachable!(),
             Self::U32(u) => u.kind(),
+            Self::Matchall(m) => m.kind(),
             Self::Other(o) => o.kind(),
         }
     }
@@ -60,6 +65,10 @@ where
             u32::KIND => Self::U32(
                 u32::Nla::parse(buf).context("failed to parse u32 nlas")?,
             ),
+            matchall::KIND => Self::Matchall(
+                matchall::Nla::parse(buf)
+                    .context("failed to parse matchall nlas")?,
+            ),
             _ => Self::Other(DefaultNla::parse(buf)?),
         })
     }